WASHINGTON — On the night before Joe Biden’s world collapsed, he sat in a picture-perfect scene with his wife by the fireside in their Delaware living room.

Biden, the hotshot senator-elect at just 30, was reflecting on the big things he would do when he got to Washington. It was one week out from Christmas in 1972, and Neilia, also 30, was addressing holiday cards as her husband rambled on. But then she interrupted his musings to share an ill premonition.

“What’s going to happen, Joey?” she asked her husband, in Biden’s later recounting. “Things are too good.”

One day later, Neilia and the couple’s 13-month old daughter, Naomi, were dead. Sons Hunter and Beau, a year and a day apart at 3 and 4, were seriously injured.

While Biden was in Washington setting up his new office, Neilia’s car had been broadsided by a tractor-trailer as she took the kids to pick out a Christmas tree.

Nothing would ever be the same. Biden was instantly transformed into a politician whose career would forever be grounded in tragedy. Loss became central to Biden’s political persona, a history he has often shared - at some points reluctantly, at others readily and on at least a few occasions with inaccuracies in the account. Now in his third bid for the White House, the painful story comes up as point of connection to voters and a personal experience on health care policy.

But Biden confidants say the history is much more than that. It’s essential to explaining the candidate’s inclination to give others, even political opponents, the benefit of the doubt. Surmounting loss helped to shape a determination to overcome hard things that friends see reflected in Biden’s recent talk about the need to work even with those “who may offend every fiber of your being,” and in his can-do attitude toward world trouble spots.

As it turned out, Biden’s passage through hardship was not to be a one-time journey but a well-traveled path. His life was later rocked by serious illness, political setbacks, and, in 2015, Beau’s death from brain cancer at age 46. There were other, less public, trials, including Hunter’s struggles as an adult with addiction.

Despite life’s cruelties, though, Biden remarried, added daughter Ashley to his family, spent 26 years in the Senate, eight as vice president and pursued the presidency off and on for more than three decades. He’s now making another run at age 76.

“He is the unluckiest person I’ve ever known personally, and he is the luckiest person I’ve ever known personally,” says longtime friend Ted Kaufman, who succeeded Biden in the Senate.

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After the accident, Biden had no interest in the Senate anymore. No ambition for anything, really. His world view shrank to taking care of the boys.

“For the first time in my life, I understood how someone could consciously decide to commit suicide,” he would later reveal.

Biden didn’t just have to deal with grief. He had the added burden of processing it in public.

On Dec. 19, 1972, the day after Neilia’s car accident, Richard Nixon’s aides briefed the president on the tragedy, spelling out the name of the unfamiliar incoming senator “B-I-D-E-N.”

Then the White House operator patches Biden through for a condolence call.

“So uh, so the, uh, but, uh, in any event, uh, I mean, looking at it in a, as you must, in terms of the future, because you, you have the great fortune of being young,” the president tells him. “And now I’m sure that, uh, she’ll be watching you from now on.”

He debated relinquishing the Senate seat he’d yet to even occupy but eventually agreed to give the job a try for six months.

Two-and-half weeks after Neilia’s death, Biden was sworn in as senator in a small chapel at the hospital in Delaware. Beau, still in traction, was wheeled into the room in his bed; Hunter, by then out of the hospital, perched on his brother’s bed for the ceremony.

Senators gave Biden broad leeway once in office. His sister Valerie moved in to take care of the boys. The new senator went home to Delaware every night to kiss them good night.

For decades to come, Biden would wrestle with the image he cut as a tragic figure and a self-described “hot commodity” on the Washington scene.

Loss became part of the Biden package. And it made for an uncomfortable fit at times.

“I am the youngest man in the Senate and I am also the victim of a tragic fate which makes me very newsworthy,” he told Washingtonian in a 1974 interview.

“I’m sure that’s why I get so many invitations all the time. I don’t accept them and people understand why.”

The conversation revealed a man still struggling with how to be in the spotlight. He at times appears boastful and also still broken. Biden shared a photo of his deceased wife in a bikini, offering that she looked “better than a Playboy bunny” and calling her “my greatest ally, my sensuous lover.” He mentioned getting Rose Kennedy dinner invitations “at least 10 times and I’ve only gone once.”

Former Sen. Bill Bradley, D-N.J., who served with Biden in the Senate for nearly two decades, says that while many a politician wrestles with hidden personal tragedies, Biden from the beginning has been open about his pain.

When people “see someone who is able to make his way through that in public, which is infinitely more difficult, they have a feeling for him as a human being,” Bradley said.

When Sen. Chris Coons’ father lay dying in hospice care, there were plenty of expressions of support and concern.

The comforting words that the Delaware Democrat heard from Biden, a longtime friend, were different.

“He knows what you’re going through,” says Coons. “He knows that you can come through it.”

He’s seen Biden do the same for countless others - the family of a lost firefighter, the parent of a son killed in Afghanistan, the widow of local restaurateur, and so many more.

Often, these strangers-turned-partners-in-grief hear a message of reassurance from Biden that’s drawn from his own experience: There will come a day, I promise you, when the thought of your son or daughter or your husband or wife “brings a smile to your lips before it brings a tear to your eye.”

They also may come away with his cellphone number.

“I have a long list of strangers who have my private number and an invitation to call,” Biden wrote in his 2017 book. “And many of them do.”

Former Democratic Rep. Steve Israel of New York says Biden called his mother in 2011 when the vice president heard that her husband had been diagnosed with lung cancer. In 2013, five months after Israel’s father died, the congressman’s mother told him, “Joe called.” Israel assumed she was reminiscing about Biden’s call in 2011.

“No,” his mother told him. “He just called a few days ago to check in on me.” He called on New Year’s Day, because the start of a new year is hard without someone you love.

Iowa state Sen. Pam Jochum, a Democrat, remembers Biden calling to comfort her after her daughter Sarah died, and then again after he got wind that her sister had died just six months later. “Good lord, woman, you’ve been through the wringer,” she remembers Biden telling her.

“The man understands the joys and sorrows of life,” Jochum said. “I think it informs his public decisions.”

For one family, though, the famed Biden reputation for empathy comes up short.

Curtis Dunn was the driver whose truck struck Neilia’s car. By all accounts, Dunn was absolved of wrongdoing in the accident, with no evidence that speeding or alcohol was a factor. Dunn, who died in 1999, never forgot that awful day, wondering aloud in future years “how the little Biden boys are doing,” recalls his daughter, 54-year-old Pamela Hamill of Newark, Delaware.

But decades later, Biden on at least two occasions, in 2001 and 2007, offered an inaccurate version of Dunn’s role in the accident, referring publicly to a truck driver who “stopped to drink” before driving and describing the driver as “a guy who allegedly - and I never pursued it - drank his lunch instead of eating his lunch.”

Hamill, dismayed by the misrepresentations, crusaded to correct the record, and got some media attention for her efforts.

Biden later called her - at first agitated about the impact the controversy was having on his own mother, who he said “had to go on anxiety medication,” in Hamill’s recounting. Further, Biden told her it was his own son, Beau, who had had to retrieve the accident report.

“Then he was very apologetic,” Hamill continued. “By this time I was in tears. He said, ‘I’m sorry, don’t cry. I will come to your home with all your family there and apologize.’” But Biden told her he would not issue a public apology, telling Hamill that it would “end up in all the trashy magazines in the grocery store.”

Hamill never took him up on the offer to meet with her family, worried about how her mother would handle it. She never heard from him again.

“I wish he would have done it publicly, but I put it to rest after that,” Hamill said.

His refusal to make a public apology, she said, “is very telling.”

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In his latest pursuit of the presidency, his third try, Biden has often been reluctant to express regret.

He’s caught flak from his Democratic rivals for his friendly relationships with political rivals. For calling Vice President Mike Pence “a decent man.” For pointing with pride to his ability to deal with “civility” with segregationists such as Democratic Sens. James Eastland of Mississippi and Herman Talmadge of Georgia long ago in order to get things done.

In both instances, Biden went on to stress that he had had sharp policy differences with his former colleagues. After resisting for a time, Biden eventually apologized for giving the “impression” that he was praising segregationists but still defended his strategy of working “even with those we find repugnant” to accomplish things.

What struck detractors as a jarring disconnect made perfect sense to Biden fans, who trace a direct line from his background of suffering to his inclination toward connection.

“It’s why he said Mike Pence is a good man,” says former Democratic Sen. Bob Kerrey of Nebraska, who spent a dozen years in the Senate with Biden. “That’s how he sees humans.”

Some see a connection, too, between Biden’s past trials and the confident way he approaches national challenges.

When Biden played down China’s threat to the U.S. - “China is going to eat our lunch? Come on, man” - he drew criticism from some of his Democratic rivals and President Donald Trump for underestimating the geopolitical challenge. But Coons saw it as a reflection of Biden’s belief in the power of individuals - and nations - to overcome great hurdles.

“What he was saying then is what he was saying to me and to so many others,” says Coons, recalling Biden’s words of comforts when his father was dying. “This is really hard but you can do it and you can get through it.”

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Nearly half a century into his political career, Biden still processes events through the frame of reference of his past travails. And he’s still prone to mentioning the tragedies of his life as political lessons.

Often, he brings up the twin tragedies of his wife and daughter’s deaths and then Beau’s death in the context of health care policy, saying he “couldn’t imagine” what it would be like if he hadn’t had good access to health care. He mentioned the accident during a speech to a firefighters union in March, six weeks before he announced his latest campaign.

“I’m going to repeat myself but we feel so deeply indebted,” he said. “In December of ‘72 when my wife was bringing home a Christmas tree, a tractor-trailer broadsided, killed my wife, killed my daughter. It took about an hour and a half, I’m told, for the jaws of life from my fire company to save my boys who in all likelihood, I’m told, would have died as well.”

He choked up last month during a speech in Iowa in which he invoked both the deaths of Beau and of his wife and daughter as he praised personal caregivers who are there to hold people’s hands when they “get really scared.”

In this, Biden is hardly alone. Many politicians use personal episodes to make political point.

Still, it was somewhat unexpected to hear him invoke his history as he defended himself against criticism that he was too physical with women.

He tries to “make a human connection” with those trying to “get through tragedy,” Biden said in a video message in which he said he understood that the boundaries of personal space have been reset in recent years.

“Over the years, knowing what I’ve been through, the things I’ve faced, I’ve found that scores, if not hundreds of people have come up to me and reached out for solace and comfort.”

Soon after, Biden went on to crack jokes about the criticism, suggesting it was an overreaction of the #Metoo era.

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When it came time for Biden to make the decision on whether to run for president in the 2016 election, his emotions over the death of Beau were still too raw.

In an interview on “The Late Show with Stephen Colbert” on Sept. 11, 2015, three months after Beau’s death, Biden opened up about his fragile state. He recalled a recent visit he had made to a military base in Colorado that had been going great until a man in the crowd called out Beau’s name and said they had served together in Iraq.

“All of a sudden I lost it,” Biden said. “I shouldn’t be saying this, but you can’t do that. You can’t do that.”

Still, Biden kept open his political options well into that October - and seethed when critics suggested he had leaked talk about Beau’s desire for him to run as part of a crass political calculation.

“The idea that I would use my son’s death to political advantage was sickening,” Biden wrote in his book about Beau’s passing, “Promise Me, Dad.”

“I didn’t think anybody would believe the charge, but I could feel my anger rise.”

On Oct. 21, 2015, at age 72, Biden announced he wouldn’t run for president - not in that election anyway.

The assumption by many was that it was the end of the road for Biden’s political career.

But less than four years later, the memory of Beau’s determination that his father stay engaged in public life factored into Biden’s decision to make another run.

Whatever happens from here, there’s a kind of liberation for Biden in knowing that he can run and lose and it still won’t be the worst thing that’s happened to him.

Kaufman, Biden’s longtime friend and political ally, says the two of them have a “difference of opinion” over how to age, Kaufman arguing that their older years should be a time to take a “more contemplative” approach to life. A few years back, Kaufman says, he sent Biden a quotation he’d found from Pope John Paul XXIII from his days as a cardinal essentially validating Kaufman’s side of their running debate.

Biden sent it back, after adding a counter message from poet Dylan Thomas:

“Do not go gentle into that night,

Old age should burn and rave at close of day;

Rage, rage against the dying of the light.”

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Associated Press news researcher Jennifer Farrar in New York contributed to this report.